It is a bad idea. I was walking down the street and saw one house with the green painted "grass colored" rock. Another house had the pebble spray painted also. It didn't look organic at all. It almost looked like hundreds of small styrofoam rocks. You know how they have those plastic boulders they sell. Imagine a bunch of small ones like that.
If you're looking for an inexpensive route. Go to craigslist. Search in the free section. "rocks"
I got about two truckloads of mexican beach pebble for free. The person ordered to much and was just happy to reclaim their driveway space. Not only that, I found about 2 or 3 other postings for free rock. This was about 6 months ago.
GO GO Gadget Hammer!!